Quas would prefer less changes from the 5e system and Theliel is saying that 5e spiritually sucks because (at some point or at some level etc) it fails to capture the (Gygaxian?) experience of giant battles and accidental TPK through a wizard derping with a fireball burning everything and everyone alive (including the tile set).
Furthermore, he reinforces his point by say Mentzer, the creative advisor to Gygax, intends for everything to feel like Armageddon when casters unleash their full arsenal - cue burning buildings, the floor is lava, corpses everywhere, flaming meteors of doom etc.
So far the tldr is that the stuff you see in BG3 is thus far aligned with what Gygax and co intended and 5e was a step back.
Then lastly he is saying that in 4th edition there was a page 82 in one of the books that had a table of what the optimal DPT should be in an effort to guide(?) the DM / or the players to seek out the correct splat books/classes/rules to make that happen where as 5e doesn't have that so combat tends to be fairly stale.
I think it is quite dangerous to make assumptions about "the spirit or the letter" of the texts.
